COMPARATIVE ANATOMY AND PHYSIOLOGY. 117 



able adaptation of means to ends; as in the construction of habitations by 

 various Insects, and especially by the social Hymenoptera. But few persons 

 will maintain that this adaptation is performed by the mind of the animal ; 

 since, on this supposition, every Bee solves a problem which has afforded 

 scope for the laborious inquiries of the acutest human mathematician.* The 

 adaptation is in the original construction of a nervous system, which should 

 occasion particular movements to be performed under particular external condi- 

 tions ; and the constancy with which these are performed by different indi- 

 viduals of the same species, when placed in the same conditions, leads at once 

 to the belief, that they must be independent of any operations so variable as 

 those of judgment and voluntary exertion. On the other hand, in the Verte- 

 brata, we find the purely instinctive movements forming a smaller proportion 

 of the whole actions, and brought under a more complete subjection to the 

 sensori-volitional system. This is evident from the greater variety which the 

 actions exhibit ; from the mode in which they are adapted to peculiar circum- 

 stances; from the degree in which they may be modified by education; and 

 from various other indications of a superior kind of Intelligence. At last, in 

 Man, those instinctive movements which are not immediately requisite (like 

 those of respiration) for the maintenance of the organic functions, are placed 

 under the control of the will. This is especially true of the locomotive organs, 

 whose reflex actions are entirely guided by the will ; being only distinguish- 

 able, when, from peculiar states of the system, the immediate influence of the 

 brain upon them is suspended. 



156. There is a third aspect, however, under which we are to consider the 

 Nervous System ; and this becomes more important in the highest division of 

 the Animal kingdom, on which we are now about to dwell. We have hitherto 

 spoken only of its influence on the contractile properties of the tissues, to 

 which it is distributed. It has, however, an important and direct connection 

 with the purely organic functions of Nutrition and Secretion ; and we shall 

 see reason to regard it as the means, not only of placing the animal in relation 

 with the external world, but of harmonizing and controlling the organic changes 

 taking place in its own structure, and of bringing these under the influence of 

 particular mental conditions. The opinion is entertained by many, that all 

 the organic functions are dependent upon the innervation supplied to them by 

 the system of nerves, which has been termed Sympathetic or vsiceral. It is 

 incumbent, however, on those who uphold the necessity of this nervous power, 



* The hexagonal form of the cell is the one in which the greatest strength, and the 

 nearest approach to the cylindrical cavity required for containing the larva, are attained, 

 with the least expenditure of material. But the instinct which directs the Bees in the 

 construction of the partition that forms the bottom or end of the cell, is of a nature 

 still more wonderful than that which governs its general shape. The bottom of each cell 

 rests upon three partitions of cells upon the opposite side of the comb; so that it is 

 rendered much stronger than if it merely divided the cavities of two cells opposed to one 

 another. The partition is not a single plane surface ; but is formed by the union of three 

 rhomboidal planes, uniting in the centre of each cell. The angles formed by the sides 

 of these rhombs, were determined by the measurements of Maraldi to be 109 28' and 

 70 32'; and these have been shown by mathematical calculation to be precisely the 

 angles at which the greatest strength and capacity can be attained with the least expen- 

 diture of wax. The solution of the problem was first attempted by Koenig, a pupil of 

 the celebrated Bernoulli; and as his result proved to differ from the observed angle by 

 only two minutes of a degree, it was presumed that the discrepancy was due to an error 

 of observation, which it was easy to account for by the smallness of the surfaces whose 

 inclination had to be measured. The question has been since taken up, however, by 

 Lord Brougham, (Appendix to his Illustrated edition of Paley's Natural Theology), who 

 has worked it out afresh, and has shown that, when certain small quantities, neglected 

 by Krenig, are properly introduced into the calculation, the result is exactly accordant 

 with observation, the Bees being thus proved to be right, and the Mathematician wrong. 



